CH661572A5 - LINEAR ACTUATOR WITH SCREW NUT SYSTEM. - Google Patents

Description

The present invention relates to a linear actuator comprising a motor of any type: electric,

hydraulic, pneumatic, the output shaft of which is kinematically linked to one of the two elements constituting a reversible screw-nut system. The second element of this screw-nut system is integral with an operating arm parallel to the system, connected, by a friction torque limiter, to an intermediate element fixed in rotation, intended to be connected to the element to be actuated.

In a known linear actuator of this kind, which is for example intended to automatically actuate a leaf of a door or a gate, it is indeed necessary that the screw-nut system used is reversible so that, when the leaf is closed, it can be opened by hand in the event of an accidental interruption of the supply current to the electric motor controlling the linear actuator. This results in a certain drawback because, when the leaf is open, it is liable to be closed by the force of the wind at a time when a person or a vehicle passes through the door or the gate, which is liable to cause an accident.

The linear actuator, according to the invention, is characterized in that the second element of the screw-nut system comprises at least a first profiled part facing outwards, designed to cooperate, when this second element occupies only one of its two extreme axial positions, with respectively a second profiled part supported by a fixed element surrounding at least locally the screw-nut system. At least one of the two profiled parts has the shape of a bayonet oriented so as to prevent the second element, when it reaches said extreme axial position, from rotating in the same direction as the motor shaft and that the first element, and to move axially from this extreme axial position. The outer side of the bayonet is capable of serving as a stop and guide, for the other profiled part, until this penetrates into the inlet of the bayonet, this other profiled part being arranged to slide on the outer side of the bayonet.

'The present invention proposes to allow the production of a linear actuator which, while being able to be actuated manually in the event of a cut in the supply current to its motor, when it occupies one of its extreme actuation positions , cannot be inadvertently actuated other than by its motor when it occupies its other extreme actuation position.

The present invention has another advantage consisting in that, when the linear actuator occupies this other extreme actuation position, it can, in the event of a power failure, be actuated manually, after the user has performed a simple maneuver. on the actuator.

The accompanying drawing illustrates, by way of example, embodiments in accordance with the present invention.

Figure 1 shows, in longitudinal section, a first embodiment of linear actuator.

2 shows, in section along II-II of Figure 1, the same first embodiment, in a first phase of operation.

3 shows, in section along II-II of Figure 1, the same first embodiment, in a second operating phase.

FIG. 4 partially represents, seen in longitudinal section, the same first embodiment, in a third operating phase.

5 shows, in section along V-V of Figure 4, the same first embodiment.

FIG. 6 shows, partially seen in longitudinal section, a second embodiment of the invention.

FIG. 7 represents, seen partially in longitudinal section, a third embodiment of the invention.

FIG. 8 shows, partially seen in longitudinal section, a fourth embodiment of the invention.

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FIG. 9 represents, seen partially in longitudinal section, a variant of the fourth embodiment of the invention.

10 shows, partially seen in longitudinal section, a variant of the first embodiment.

FIG. 11 shows, partially seen in longitudinal section, another variant of the first embodiment.

As shown in FIGS. 1 to 5, the linear actuator according to the invention comprises a motor 1, for example an electric motor, the output shaft 2 of which is angularly secured, by a pin 3, of the extreme part 4 ′, of the first element of a screw-nut system, constituted in this example by the screw 4, the second element of this system being constituted by a nut 5 constantly engaged with the screw 4 which is for example a screw on the right. The inclination of the thread and the number of threads are such that the screw-nut system is reversible. The extreme part 4 ′ is supported for example by a ball bearing 6 held between two fixed rings 7 and 8 secured to the first end 9 ′ of a casing 9. The nut 5 is secured to a parallel operating arm 10 to the screw-nut system, constituted in this example by a tube which is intended to slide and rotate in a cylindrical bearing 11 provided in the second end 9 "of the casing 9 (FIG. 1).

The free end 10 'of the operating arm 10, external to the casing 9, contains in a cylindrical housing 12 axial, a friction torque limiter 13 connecting this free end 10' to an end 14 'of an intermediate element 14 , constituted for example by a yoke, end pivotally mounted in the housing 12 by a ball bearing 15. This intermediate element 14 is connected to an element to be actuated 16 forming part for example of a gate leaf, and is made fixed in rotation by this element 16.

The nut 5 comprises, on the side opposite to the tubular arm 10, two profiled parts 21 diametrically opposite one another, turned towards the outside of this nut 5. These two parts 21 are provided to cooperate, when this nut 5 occupies only one of its two extreme axial positions (FIGS. 4 and 5), with respectively two profiled parts 22 supported by the fixed ring 8, these two profiled parts 22 locally surrounding the screw-nut system. In this example, the profiled parts 22 have the shape of a bayonet oriented so as to prevent the nut 5, when it reaches said extreme axial position, by their stops 22a (FIGS. 1 and 4), from turning in the same direction 23 (Figure 1) that the motor shaft 2 and that the screw 4, and by their inner sides 22b, to move axially from this extreme axial position.

In this example, the two profiled parts 22 in the form of bayonets are connected to a face 8a of the ring 8 which supports them, which face is radial. The inner side 22b of each bayonet 22 is parallel to this radial face 8a. On the other hand, the outer side 22c opposite the inner side 22b of each bayonet 2 is, in this example, inclined relative to this radial face 8a, in a direction opposite to that of the pitch of the screw-nut system, it ie left in this example. The two profiled parts 21 also have an outer front sides 21a which is inclined in the same way as the outer sides 22c, so that they can serve as an axial stop along 24, and a guide along 23 to the profiled parts 21 until that each enters the inlet 22d of a bayonet 22.

When the screw 4 is rotated by the motor shaft 2 in the opposite direction to 23, the nut 5 only moves axially, in the opposite direction to 24, until the operating arm 10 is extended substantially at maximum, to control the closing of the gate leaf. When the leaf 16 is completely closed, the axial movement of the arm 10 is prevented, and the friction of the torque limiter 13 allows the arm 10 to rotate at the same time as the screw 4

until the power to motor 1 is cut off.

If a power failure then occurs, it is possible, after unlocking the leaf 16 of the gate, to open it by hand, which causes, the screw-nut system being reversed; -5 ble, the shortening of the arm 10 by rotation in opposite direction of 23 of the nut 5 on the screw 4 which is kept fixed in rotation by the motor 1. It is the friction of the torque limiter 13 which allows this rotation of the nut 5, in the since the friction adjustment is such that the value of the friction cou-io pie is less than the reversible torque of motor 1.

This rotation ceases when the inclined external sides 21a of the profiled parts 21 of the nut 5 come into contact with the inclined external sides 22c of the clear bayonets 22.

In normal operation, in the absence of a power failure, it is the motor shaft 2, turning along 23 (FIG. 1), which causes the axial displacement only, along 24, of the nut 5 and the arm of operation 10, therefore the pro-aggressive opening of the leaf] 16. As soon as the inclined external sides 21a of the first profiled parts 21 come into contact with the inclined external sides 22c of the second profiled parts 22 (Figures 1 and 2), l nut 5 and arm 10 rotate along 23 in the same direction as screw 4, the outer sides 25 laughing 21a and 22c sliding against each other, this rotation being permitted by the friction torque limiter 13. As soon as the first profiled parts 21 project beyond the lowest end of the inclined external sides 22 (FIG. 3), they move axially only again, along line 24, "until the nut 5 comes to bear on a ring, not shown in the drawing, secured to the extreme part 4 'of the screw 4. The nut 5 then turns again along 23 at the same time as the screw 4 until the first profiled parts 21 respectively penetrate into the second profiled parts 22 in the form of bayonets (FIGS. 4 and 5), and finally come to bear against the fixed stops 22a, behind the inner sides 22b. The electric motor 1 is then cut off.

If, during the following axial displacement 24, of the nut 5, 4 »the first profiled parts 21 do not come into contact with the external sides 22c of the second profiled parts 22. but pass before or after these inclined external sides 22c, the nut 5 continues its axial movement until they come into abutment against the ring secured to the extreme part 4 'of the screw 4. As described in the preceding paragraph, the nut 5 rotates along 23 at the same time that the screw 4 until its first profiled parts 21 penetrate into the second profiled parts 22 in the form of bayonets.

™ If a pull is exerted inadvertently in the opposite direction to 24, for example by the wind acting on the leaf 16 open, this pull tends to cause the rotation along 23, of the arm 10 and of the nut 5, against the action of the friction of the torque limiter 13. This rotation is prevented 55 by the second profiled parts 22 in the form of bayonets which retain the first profiled parts 21 of the nut 5. Any untimely closing of the leaf 16 is thus prevented.

When the motor 1 drives its shaft 2 in rotation in the opposite direction from 23, the nut 5, prevented from moving axially by the inner sides 22b, is first driven in rotation in the same direction, by operating the friction of the torque limiter 13. As soon as the first profiled parts 21 are released from the second fixed profiled parts 22, f'1 the nut 5 and the arm 10 are free to move axially again, in the opposite direction to 24, as described previously.

In the event of a power failure, leaf 16 being open, it is possible to unblock the actuator voluntarily

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linear, to manually close the leaf 16. For this, it suffices to manually rotate, in opposite direction to 23, the free end 10 ′ of the operating arm 10, against the action of the friction torque limiter. As soon as the first profiled parts 21 are released from the second fixed profiled parts 22, it suffices to act on the leaf 16 to pull on the yoke 14, tending to lengthen the arm 10, which causes the rotation along 23, arm 10 and nut 5, against the action of the friction torque limiter 13.

The second embodiment of the invention, partially shown in Figure 6, differs from the first (Figures 1 to 5) only in that the outer side 22c of each second profiled part 22 in the shape of a bayonet is, like the side interior 22b, parallel to the radial face 8a. In addition, each first profiled part 21, supported by a pusher 30, is movable on the periphery of the nut 5, only axially, towards the rear in the opposite direction to 24, against the action of a compression spring 28 , in a longitudinal groove 29 provided in the nut 5. In addition, the front outer side 21a of each first profiled part 21 is no longer inclined but parallel to the face 8a. All the other constituent elements are identical to those of the first embodiment (FIGS. 1 to 5).

When the screw 4 is driven in rotation along 23 by the motor shaft 2, the arm 10 and the nut 5 move axially only along 24, in the direction of the second fixed profiled parts 22. If the latter are on the trajectory of the first profiled parts 21, these first parts 21 finally come into contact with the second parts 22 and are thus immobilized axially. As soon as the springs 28 are sufficiently compressed, the friction of the torque limiter 13 operates, and the arm 10 and the nut 5 rotate along 23 while the springs 28 continue to compress. As soon as the first profiled parts 21 exceed the rear ends of the outer sides 22c, they move abruptly along 24 under the action of the springs 28 and, their rotation following 23 resuming, they penetrate into the second profiled parts 22 in the form of bayonets, and reach the position shown in Figure 6. The rest of the operation is identical to that previously described (Figures 1 to 5).

The third embodiment, partially shown in Figure 7, differs from the first (Figures 1 to 5) only in that the inner side 22b of each second profiled part 22 is, like the outer side 22c, inclined relative to the radial face 8a in the opposite direction to that of the pitch of the screw-nut system, therefore to the left in this example. This inclination of the inner sides 22b is advantageously less than that of the threads of the screw-nut system, so that these inner sides 22b can oppose any axial displacement, in the opposite direction of 24, of the first profiled parts 21 which are housed behind these interior sides 22b, when a pull is carried out inadvertently in this direction on the arm 10. In addition, the side 21b opposite the side 21a, of each first profiled part 21 is advantageously inclined in the same direction as this side 21a and than the inner side 22b.

The fourth embodiment, partially shown in Figure 8, differs from the third embodiment, described above (Figure 7), only in that the second sections 22 shaped in the form of bayonets are connected to a face 8b of the element 8 which supports them, face which is, not radial like the previous face 8a, but inclined in an opposite direction due to that of the pitch of the screw-nut system, therefore to the left in this example, like the sides 21a, 21b and 22b, 22c.

The operation of this fourth embodiment is similar to that of the other embodiments previously described (FIGS. 1 to 7). The only difference lies in the fact that, in order to close the leaf by hand, in the event of a power failure, it is necessary, at the same time as it is manually rotated in the opposite direction to 23, the free end 10 'of the arm 10, to simultaneously exert an axial traction on this arm 10, so that the first profiled parts 21 can rotate despite the presence of the corresponding inclined faces 8b.

According to a variant of this fourth embodiment, shown partially in FIG. 9, the inclined face 8b to which the profiled part 22 in the form of a bayonet is connected, is arranged in the extension of the corresponding external side 22c of a bayonet. In this way, whatever the points where the first profiled parts 21 come into contact with the inclined outer sides 22c or with their extensions 8b, during their axial displacement along 24, they then follow these inclined sides 22c and 8b, before finally be housed in the respective profiled parts 22 in the form of bayonets, by turning along 23.

According to a particular case of this variant, not shown in the drawing, the two sides, inside 22b and outside 22c, of each second profiled part 22 in the shape of a bayonet, and the corresponding inclined face 8b to which the bayonet is connected, constitute a thread, with two threads in this example, opposite to that of the screw-nut system. In this case, each outer side 22c constitutes the inlet of one of the two threads with which cooperate, either first profiled parts 21, or a corresponding pitch thread, provided around the periphery of the nut 5.

Without departing from the scope of the present invention, in all the embodiments which have just been described, the profiled part or parts 22 in the form of bayonets, instead of being fixed, integral with the ring 8, can be movable, integral of nut 5 (figure 10). In FIG. 10 is shown, for example, a variant of the first embodiment (FIGS. 1 to 5) in which the profiled parts 22 in the form of bayonets, as well as the face 8a which supports them, form part of the nut 5 secured to the arm 10. As for the profiled parts 21, they are secured to a fixed extension 8c of the ring 8. The operation of the assembly identical to that of the first embodiment (FIGS. 1 to 5).

Likewise, in all the embodiments described above (FIGS. 1 to 9), the profiled parts cooperating together can be constituted only by profiled parts 22 in the form of bayonets. Thus, in Figure 11, is shown, for example, another variant of the first embodiment (Figures 1 to 5), in which the two profiled parts 22 in the form of bayonets of the actuator of Figure 1, cooperate respectively with two profiled parts 22 ', identical to the previous ones but oriented in opposite directions, integral with the nut 5. The operation of the assembly is identical to that of the first embodiment (Figures 1 to 5).

In all the other embodiments shown in the drawing, it is the screw 4 which is secured to the shaft 2 of the motor. The present invention is also applicable in the case where it is the nut 5 which is integral with this shaft 2, the screw 4 being axially displaceable relative to the nut 5, for example in an axial housing provided through the motor shaft 2, the profiled parts facing outwards being for example supported by a socket integral with the screw 4, comprising the profiled parts 21, or 22 as the case may be, on its outer periphery.

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Claims (7)

661,572 2 1. Linear actuator comprising a motor (1) whose output shaft (2) is kinematically linked to one (4) of the two elements constituting a reversible screw-nut system, the second element (5) of this screw system -nut being integral with an operating arm (10) parallel to the system, connected, by a friction torque limiter (13), to an intermediate element (14), fixed in rotation, intended to be connected to the element to be actuated (16), characterized in that the second element (5) of the screw-nut system comprises at least one first profiled part (21) facing outwards, designed to cooperate, when this second element occupies only one of its two extreme axial positions, with respectively a second profiled part (22) supported by a fixed element (8), surrounding at least locally the screw-nut system, at least one (22) of the two profiled parts having the form of a bayonet oriented so as to prevent the second element (5), when it reaches said extr axial position same, to rotate in the same direction as the motor shaft (2) and as the first element (4), and to deviate axially from this extreme axial position, the outer side (22c) of the bayonet being capable of serve as a stop and guide, for the other profiled part (21), until this penetrates into the inlet (22d) of the bayonet, this other profiled part being arranged to slide on the outer side ( 22c) bayonet. 2. Linear actuator according to claim 1, characterized in that the profiled part (22) in the form of a bayonet is connected to a face (8a) of the element (8) which supports it, which is radial, the inner side ( 22b) of the bayonet being parallel to this radial face (8a), and the outer side (22c) being inclined relative to this face in a direction opposite to that of the pitch of the screw-nut system. 3. Linear actuator according to claim 1, characterized in that the profiled part (22) in the form of a bayonet is connected to a face (8a) of the element (8) which supports it, which is radial, on both sides, inside (22b) and outside (22c), of the bayonet being parallel to this radial face (8a), and the first profiled part (21) being movable on the second element (5) of the screw-nut system, axially only, towards the rear, against the action of a compression spring (28). 4. Linear actuator according to claim 1, characterized in that the profiled part (22) in the form of a bayonet is connected to a face (8a) of the element (8) which supports it, which is radial, on both sides, inside (22b) and outside (22c), the bayonet being inclined relative to this face (8a) in a direction opposite to that of the pitch of the screw-nut system. 5. Linear actuator according to claim 1, characterized in that the profiled part (22) in the form of a bayonet is connected to a face (8b) of the element (8) which supports it, which is inclined in an opposite direction from that of the pitch of the screw-nut system, same as the two sides, inside (22b) and outside (22c), of the bayonet. 6. Linear actuator according to claim 5, characterized in that the inclined face (8b) to which the profiled part (22) in the form of a bayonet is connected, is arranged in the extension of the inclined external side (22c) of a bayonet . 7. Linear actuator according to claim 6, characterized in that the two sides, interior (22b) and exterior (22c), of the profiled part (22) in the form of a bayonet, and the inclined face (8b) to which is connected the bayonet, constitute a thread in the opposite direction to that of the screw-nut system.